1. Field of the Invention
The present invention relates to production plant automation and, more particularly, to a method for collision-free transfer of a plant from an off mode, i.e., a substantially off mode, to an operating mode.
2. Description of the Related Art
Production plants, such as automated production plants, can normally be changed over from an operating mode into a substantially off mode, which is also referred to as standby mode. Such a substantially off mode is characterized by the fact that it requires only a very small amount of power in comparison to the power required for the operating mode, which is desirable in principle with respect to the environment and operational costs.
A problem exists in that, when a plant is transferred from the substantially off mode back to the operating mode, all of the relevant operational states need to be brought to the respective same state of knowledge that existed prior to the substantially off mode, corresponding to the plant function. This requirement is to ensure collision-free startup of the plant, which relates both to dynamic and static states of connected process sections and the temporal causalities thereof. All of the foregoing, is associated with a high degree of complexity. In particular, the temporal causalities, such as the temporal interaction of individual process sections, are lost during the transition of the plant from the operating mode to the substantially off mode, for which reason the plant needs to be restarted. Correspondingly, the power saving option is usually not used during down times of production plants by transferring the production plant to the substantially off mode.
Collision-free transfer of a production plant from a completely off mode to an operating mode is associated with even greater time expenditure. Usually, the individual production plant components that are associated with the connected process sections need to first be brought into a predefined starting position to initiate the operating mode starting from this starting position.